Structure of heat pipe with adjustable working temperature range

ABSTRACT

A structure of heat pipe with adjustable working temperature range are provided. The heat pipe includes a tube, a capillary structure and a working liquid. The tube includes a passage having a length direction and a diameter direction. Besides, a part of the tube has a pressed deformation zone in the pipe diameter direction, and the pressed cross-sectional area of the deformation zone in the diameter direction is reduced by a reduction ratio with respect to an original cross-sectional area before pressing, so that the deformation zone has a higher fluid resistance. Thereby, the heat pipe can be operated under a certain working temperature range, and the working object can achieve the working efficiency.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional application of U.S. Non-Provisionalapplication Ser. No. 16/546,568 filed Aug. 21, 2019, which isincorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention generally relates to a heat pipe and, inparticular to a structure of heat pipe with adjustable workingtemperature range.

Description of Related Art

A heat pipe is provided with a vacuum tube filled with a working fluidinside. The working principle of the heat pipe is that the working fluidhas a phase change after being heated for heat exchange, and then theworking fluid will be cooled to return back to a liquid state to berecirculated to use. The implement method of the heat pipe is to put theevaporation section of the heat pipe attached on a heating electronicelement, so that the heat of the electronic component is absorbed by theevaporation section of the heat pipe, and then the heat will betransmitted to the condensation section through the heat pipe, therebythe heat dissipation effect can be achieved.

Moreover, the existing heat pipe has a very small temperature differencebetween the evaporation section and the condensation section to achievea good heat dissipation efficiency; thus, the heat exchange of theworking object is carried out through the phase change of the workingfluid, and the working object can be prevented from damages ofoverheating or a deteriorated system efficiency. However, in somespecial environments (such as in extremely cold environments),electronic components may not be able to achieve a proper operatingtemperature due to the small temperature difference, and that may leadto electronic components cannot maximize their performance.

Therefore, the purpose of the present invention is to provide a heatpipe which can be operated at a certain temperature, so that the heatpipe will not be operated under a low ambient temperature and theelectronic component having a low heating temperature; on the otherhand, the heat pipe will start to be operated while the electroniccomponent having a high heating temperature.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to provide amanufacturing method of heat pipe with adjustable working temperaturerange, so that the heat pipe can be operated at a certain workingtemperature range, and it can make the working object to achieve thework efficiency.

In order to achieve the object mentioned above, the present inventionprovides a manufacturing method of heat pipe with adjustable workingtemperature range, comprising: a) providing a heat pipe for attaching aworking object for heat exchange; the heat pipe including a tube, acapillary structure disposed on an inner wall of the tube, and a workingliquid disposed in the tube; the tube comprising a passage having alength direction and a diameter direction perpendicular to the lengthdirection; the working liquid absorbing heat of the working object andconverting into a vapor phase, and the working liquid passing thepassage to perform a condensation reaction along the length directionand condensing back into the working liquid; the working liquid movingto a location where the working object attached thereto through thecapillary structure and absorbing heat of the working object; b)pressing uniformly on a part of the tube in the pipe diameter directionby a means of processing to form a deformation zone, and a pressedcross-sectional area of the deformation zone after pressing in thediameter direction reduced by a reduction ratio with respect to anoriginal cross-sectional area before pressing, so that the deformationzone has a higher fluid resistance, wherein the reduction ratio of thepressed cross-sectional area of the deformation zone in the diameterdirection is determined by the following method: c) setting the heatpipe being capable of performing heat exchange of the working object inan ambient temperature range and making a working temperature of theworking object to be in a target working temperature range; d) providinga testing chamber and disposing the heat pipe with the working objectattached thereto, wherein a temperature of the testing chamber iscontrolled at the ambient temperature range; e) operating the workingobject at the ambient temperature range in the testing chamber andmeasuring an actual temperature range during the operation of theworking object; and f) reducing a cross-sectional area of the passage inthe pipe diameter direction by the reduction ratio, so that the actualtemperature range will fall within the target working temperature range.

Accordingly, another object of the present invention is to provide astructure of heat pipe with adjustable working temperature rangecomprising a tube, a capillary structure disposed on an inner wall ofthe tube, and a working liquid disposed in the tube. The tube comprisesa passage having a length direction and a diameter directionperpendicular to the length direction. The working liquid absorbs heatof the working object and converting into a vapor phase and passing thepassage to perform a condensation reaction along the length directionand condensing back to the working liquid. The working liquid moves to alocation where the working object attached thereto and absorbing heat ofthe working object; wherein a part of the tube has a deformation zone inthe pipe diameter direction, and a cross-sectional area of thedeformation zone in the diameter direction is reduced by a reductionratio with respect to an original cross-sectional area before pressing,so that the deformation zone has a higher fluid resistance.

Comparing to the prior art, the heat pipe of the present invention haspressed uniformly on a part of the tube in the pipe diameter directionto form a deformation zone. In a low temperature environment, there is ahigh vapor flow resistance between the evaporation section and thecondensation section, thus the temperature difference is increased, sothat the heat pipe can be operated efficiently under a certain operatingtemperature range, and the working temperature of the working object canbe increased to an appropriate working temperature to work. Moreover,when the heat pipe is in a high temperature environment, the workingfluid has a large vapor volume at the high temperature, thus theinternal pressure of the heat pipe will be increased and the workingvapor is pushed from the evaporation section to the condensation sectionrapidly; thereby the heat transfer efficiency is improved, and theevaporation section and the condensation section will have a smalltemperature difference. Therefore, the heat pipe can be operated under acertain working temperature range, and the working object not only canbe prevented from being overheated and damaged, but also the systemperformance efficiency will be remained.

BRIEF DESCRIPTION OF THE DRAWINGS

The features of the invention believed to be novel are set forth withparticularity in the appended claims. The invention itself, however, maybe best understood by reference to the following detailed description ofthe invention, which describes a number of exemplary embodiments of theinvention, taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a perspective schematic view of heat pipe with adjustableworking temperature range of the present invention;

FIG. 2 and FIG. 3 are cross sectional views of heat pipe with adjustableworking temperature range in two directions of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

In cooperation with attached drawings, the technical contents anddetailed description of the invention are described thereinafteraccording to a number of preferable embodiments, being not used to limitits executing scope. Any equivalent variation and modification madeaccording to appended claims is all covered by the claims claimed by thepresent invention.

Please refer to FIG. 1 to FIG. 3, which depict a perspective schematicview and two cross sectional views of heat pipe with adjustable workingtemperature range of the present invention. The heat pipe 1 withadjustable working temperature range includes a tube 10, a capillarystructure 20 disposed on an inner wall of the tube, and a working liquid30 disposed in the tube 10. In addition, the heat pipe 1 is provided forattaching a working object (not shown) for heat exchange. More detaildescriptions of the manufacturing method and structure of heat pipe 1with adjustable working temperature range are as follows.

In the present embodiment, the manufacturing method of the heat pipe 1includes: a) providing a heat pipe 1, and the heat pipe 1 includes atube 10, a capillary structure 20 disposed on an inner wall of the tube,and a working liquid 30 disposed in the tube 10. The tube 10 comprises apassage 100 having a length direction 101 and a diameter direction 102perpendicular to the length direction 101. Besides, the working liquid30 absorbs heat of the working object and then converts into a vaporphase, and the working liquid 30 passes the passage 100 to perform acondensation reaction and condenses back into the working liquid 30along the length direction 101. The working liquid 30 moves to alocation where the heat pipe 1 attached thereto and absorbs heat of theworking object.

Specifically, the tube 10 has a deformation zone 11, a first section 12and a second section 13 located at opposite sides of the deformationzone 11. Preferably, the deformation zone 11 has a length shorter thanthat of the first section 12 and the second section 13. It is worthy tonote that the length of the deformation zone 11 is not limited, but theresistance of the vapor can be achieved when the vapor passes throughthe deformation zone 11.

Furthermore, the manufacturing method of heat pipe 1 further includes:b) pressing uniformly on a part of the tube 10 in the pipe diameterdirection 102 by a means of processing to form a deformation zone 11,and a pressed cross-sectional area A′ of the deformation zone 11 afterpressing in the diameter direction 102 is reduced by a reduction ratio Pwith respect to an original cross-sectional area A before pressing.Thereby, the deformation zone 11 can have a higher fluid resistance,wherein the reduction ratio P of the cross-sectional area of thedeformation zone 11 in the diameter direction 102 is determined by thefollowing method.

With furthering, the manufacturing method of heat pipe 1 also includes:c) setting the heat pipe 1 being capable of performing heat exchange ofthe working object in an ambient temperature range and making a workingtemperature of the working object to be in a target working temperaturerange.

Moreover, the manufacturing method of heat pipe 1 also includes: d)providing a testing chamber and disposing the heat pipe 1 with theworking object attached thereto, wherein a temperature of the testingchamber is controlled at the ambient temperature range. Besides, themanufacturing method of heat pipe 1 includes: e) operating the workingobject at the ambient temperature range in the testing chamber andmeasuring an actual temperature range during the operation of theworking object. At last, the manufacturing method of heat pipe 1includes: f) reducing a cross-sectional area of the passage 100 in thepipe diameter direction 102 by the reduction ratio P, so that the actualtemperature range will fall within the target working temperature range.

In real practice, the reduction ratio P is set to be 25% to 75%, and thereduction ratio P can be adjusted according to the actual temperaturerange of the working object during operation. For example, when thereduction ratio P is set to be 75%, it means that the pressedcross-sectional area A′ after pressing is only 25% of the originalcross-sectional area A.

In more detail, the ambient temperature range includes a high ambienttemperature and a low ambient temperature; besides, in e), the actualtemperature range includes a high actual temperature and a low actualtemperature. Moreover, the high actual temperature is an operatingtemperature of the working object when the testing chamber is operatedat the high ambient temperature, and the low actual temperature isanother operating temperature of the working object when the testingchamber is operated at the low ambient temperature. It is worthy to notethat, the operating temperature of the working object is measured undera normal loading.

For example, in the present embodiment, when the heat pipe 1 is operatedat the low ambient environment temperature, such as the originalcross-sectional area A of the tube 10 of the heat pipe 1 is set to be0.015 cm², and the temperature difference between the evaporationsection and the condensation section is very small of 2.27° C. Then aportion of the heat pipe 10 is uniformly pressed in the pipe diameterdirection 102 to form the deformation zone 11. The pressedcross-sectional area A′ of the deformation zone 11 in the pipe diameterdirection 102 is reduced by 25%, 50%, and 75% separately with respect tothe original cross-sectional area A before pressing, thus, the pressedcross-sectional area A′ will account for 75%, 50%, and 25% of theoriginal cross-sectional area A to be 0.012 cm², 0.008 cm², and 0.004cm² respectively. In addition, the temperature difference between theevaporation section and the condensation section will increase to be3.03° C., 4.55° C. and 9.10° C. respectively.

We can learn from the above example that, the tube 10 of the heat pipe 1is partially pressed uniformly in the tube diameter direction 102 toform a deformation zone 11. For example, when the reduction ratio is 75%(that is, the pressed cross-sectional area A′ accounts for 25% of theoriginal cross-sectional area A), the temperature difference between theevaporation section and the condensation section will be increased to9.10° C. At this time, the temperature difference between theevaporation section and the condensation section of the heat pipe 1 isincreased to reduce the heat dissipation efficiency when the heat pipe 1is attached to the working object for heat exchange. Therefore, the heatpipe 1 starts heat exchange after the working object reaches a certaintemperature, so that the heat pipe 1 can be operated under a certainworking temperature range. Thereby the working temperature of theworking object will be increased to an appropriate working temperatureto work.

In addition, please refer to the following table, which shows theexperimental data obtained from the heat pipe manufactured by theaforementioned method.

H TL TH AT (mm) (° C.) (° C.) (° C.) 2.0 23.9 78.7 54.8 0.7 30.6 78.748.1 0.4 37.6 80.5 42.9

The above table can be checked in conjunction with FIG. 3. The height ofthe heat pipe 1 is 2 mm before pressing; furthermore, the temperature(low actual temperature TL) measured on the surface of the workingobject, a processor for example, is 23.9° C. when the heat pipe 1 isoperated at 0° C. of a low ambient temperature before the heat pipe 1 ispressed. Additionally, the temperature (high actual temperature TH)measured on the surface of the working object, a processor for example,is 78.7° C. when the heat pipe 1 is operated at 70° C. of a high ambienttemperature. Accordingly, the temperature difference ΔT between the lowactual temperature TL and the high actual temperature TH of the workingobject is 54.8° C.

Moreover, when the heat pipe 1 is uniformly pressed to reduce the heatpipe height H to be 0.7 mm (about one third of the original height), thetemperature difference ΔT between the low actual temperature TL and thehigh actual temperature TH of the working object is 48.1° C. Similarly,when the heat pipe 1 is uniformly pressed to reduce the heat pipe heightH to be 0.4 mm (about one-fifth of the original height), the temperaturedifference ΔT between the low actual temperature TL and the high actualtemperature TH of the working object is 42.9° C.

It can be known from the above experimental data that the internal spaceof the heat pipe 1 of the present invention becomes small after beinguniformly pressed. In this case, both the low actual temperature TL andthe high actual temperature TH of the heat pipe 1 are increased.Moreover, the increase of the low actual temperature TL allows theworking object to reach a certain temperature before the heat exchangebegins. In addition, the temperature difference ΔT of the heat pipe 1 isreduced when it operates at a higher temperature of the high ambienttemperature and low ambient temperature.

It should be noted that, in the present invention, when the heat pipe 1is in a high temperature environment, the internal pressure of the heatpipe 1 is increased by phase changes of the working fluid, so that theworking vapor can be pushed quickly from the evaporation section to thecondensation section because of the high-temperature vapor havingcharacteristic of a large volume. Therefore, the heat conductionefficiency can be improved, and the evaporation section and thecondensation section will have a small temperature difference. In thisway, the working object can be prevented from being overheated anddamaged, and the system performance efficiency will not be deteriorated.

In addition, the heat pipe 1 of the present invention is subjected tothe foregoing method and plural tests. When a user sets the targetworking temperature range, the reduction ratio P can be obtained througha computer program.

Although the present invention has been described with reference to thepreferred embodiment thereof, it will be understood that the inventionis not limited to the details thereof. Various substitutions andimprovements have been suggested in the foregoing description, andothers will occur to those of ordinary skill in the art. Therefore, allsuch substitutions and improvements are intended to be embraced withinthe scope of the invention as defined in the appended claims.

What is claimed is:
 1. A structure of heat pipe with adjustable workingtemperature range, comprising a tube, a capillary structure disposed onan inner wall of the tube, and a working liquid disposed in the tube;the tube comprising a passage having a length direction and a diameterdirection perpendicular to the length direction; the working liquidabsorbing heat of the working object and being converted into a vaporphase and passing the passage to perform a condensation reaction alongthe length direction and condensing back to the working liquid; theworking liquid moving to a location where the working object attachedthereto and absorbing heat of the working object; wherein a part of thetube having a deformation zone in the pipe diameter direction, and across-sectional area of the deformation zone in the diameter directionreduced by a reduction ratio with respect to an original cross-sectionalarea before the deformation zone being pressed, so that the deformationzone having a higher fluid resistance.
 2. The structure of heat pipewith adjustable working temperature range according to claim 1, whereinthe tube includes a first section and a second section located atopposite sides of the deformation zone; the deformation zone has alength shorter than that of the first section and the second section 3.The structure of heat pipe with adjustable working temperature rangeaccording to claim 1, wherein the reduction ratio is 25% to 75%.
 4. Thestructure of heat pipe with adjustable working temperature rangeaccording to claim 3, wherein the reduction ratio is 75%.